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T Amano

Publications and source records attributed to T Amano.

At least 109 records · Page 6Linked to original sources
PubMed1999

Expression of Fas-Fas ligand in murine testis.

PROBLEM: During spermatogenesis, it has been suggested that the number of germ cells to be matured is regulated and restricted through the apoptotic mechanism. In the present study, we investigated the expression and apoptotic role of Fas and Fas ligand (L) in the murine testis. METHOD OF STUDY: The expression of Fas-FasL in the murine testis was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR)-Southern blot hybridization, in situ hybridization, and Western blot methods. The terminal deoxynucleotide transferase mediated dUTP-nick end label (TUNEL) and DNA fragmentation methods were applied to detect the generation of apoptosis in germ cells. RESULTS: By means of RT-PCR-Southern blot hybridization, we demonstrated the positive expression of Fas in testicular germ cells, and of FasL in testicular cells. supporting the findings with in situ hybridization that Fas was localized in germ cells, whereas FasL was localized in Sertoli cells of murine testis. A specific band at 45 kDa was obtained in the lysates from testis and germ cells with Western blot analysis. Then, the co-incubation of germ cells with Spodoptera frugiperda (Sf9)-FasL cells in vitro resulted in the induction of apoptosis in germ cells detected by the TUNEL method. Furthermore, DNA fragmented ladders were also demonstrated in germ cells co-incubated with Sf9-FasL cells. CONCLUSION: Fas-FasL system seemed to play an apoptotic role in spermatogenesis by the molecular interaction between FasL on Sertoli cells and Fas on germ cells.

Animals↗
PubMed1999

[A case of intrascrotal extratesticular schwannoma].

A 71-year-old man visited our hospital with a complaint of a right intrascrotal mass. An elastic hard mass was palpable in the right intrascrotal extratesticular space. Ultrasonography, computed tomographic scan and magnetic resonance imaging showed a left intrascrotal extratesticular tumor. However, preoperative diagnosis was not decided. Tumor resection was performed, and the histological diagnosis was schwannoma. Intrascrotal extratesticular schwannoma is very rare, and this case was considered as the second report in Japan.

Aged↗
PubMed1999

A case of idiopathic deep vein thrombosis improved with glucocorticoid therapy.

A healthy, middle-aged Japanese man with no family history of thrombotic disorders presented with acute abdominal pain due to ischemic colitis. Two months later, he developed left leg pain and swelling. A venogram of the lower limbs, computed tomography, and a scintigram of pulmonary blood flow revealed deep vein thrombosis of the left lower limb extending to the inferior vena cava and emboli of both pulmonary arteries with bilateral pleural effusions. The responsible coagulation disorder was not detected in this case. Since these thrombi were refractory to the thrombolytic therapy with urokinase and anticoagulant therapy with warfarin, prednisolone was chosen for the suppression of accompanying thrombophlebitis. Two months following the initiation of prednisolone (20 mg/day), the venous thrombosis, abnormal pulmonary shadows, and pleural effusions had completely resolved. This case demonstrates the successful treatment of idiopathic venous and pulmonary thrombosis with glucocorticoids.

Administration, Oral↗
PubMed1999

[Temporal lobe epilepsy associated with old intracerebral hemorrhage due to capillary telangiectasis in the temporal lobe: case report].

A case of 45-year-old female, who presented with temporal lobe epilepsy was reported. The patient was found to have old intracerebral hemorrhage due to capillary telangiectasis in the temporal lobe. On the intraoperative electrocorticography, frequent paroxysmal activities were recorded independently both on the medial and lateral aspects of the temporal lobe. Even after resection of the lateral temporal lobe, frequent paroxysmal discharges were noted on the hippocampus. Histologically, there are astrogliosis and hemosiderin deposits in the white matter around the telangiectasis and the old hematoma. It is postulated that the hippocampus gained secondary epileptogenicity.

Adult↗
PubMed1999

[Influence of scalp shaving on prevention of postoperative intracranial infection].

Shaving of the whole scalp is ordinarily performed prior to neurosurgical operation. Although it is performed in order to prevent postoperative intracranial infection, there has been no apparent basis for this practice published in previous reports. We examined whether shaving the whole scalp reduced the rate of postoperative infection or not. We divided 274 cases, who received their first intracranial operation in the last 2 years, into two groups; a whole shaving group and a partial shaving group. We compared the rate of postoperative intracranial infection between the two groups according to age, diagnosis, operation, operation time and placement of drainage. Overall, 12 cases out of 274 (4.38%) had postoperative intracranial infection. The long operation time and the long term placement of drainage mechanism increased the postoperative intracranial infection rate. There was no postoperative intracranial infection in 74 patients who received burr-hole/twist-drill operation. As for craniotomy/craniectomy operations, 7 cases out of 83 (8.4%) in the partial scalp-shaving group whole scalp shaving group and 5 cases out of 117 (4.2%) had postoperative intracranial infections. Thus, there was no significant difference in the rate of postoperative intracranial infection between the two groups, if anything, the whole scalp shaving group tended to show a higher rate. According to these results, partial scalp shaving did not increase the rate of postoperative intracranial infection. Considering that patients who have lost their hair find it embarrassing to return to society, it is well to know that the whole scalp shaving is not absolutely necessary for all first craniotomy.

Craniotomy↗
PubMed1999

[Phase 2 clinical study of 123I-IBF, a dopamine D2 receptor imaging agent, to evaluate clinical efficacy and safety in Parkinson's disease and Parkinson syndromes].

A Phase 2 multicenter trial of 123I-IBF, (S)-5-iodo-7-N-[(1-ethyl-2- pyrrolidinyl)methyl]carboxamido-2,3-dihydrobenzofuran, was conducted to evaluate its clinical efficacy and safety in 158 patients with Parkinson's disease (PD) or Parkinson syndromes (PS). SPECT data were acquired at two hours (2H-SPECT), after intravenous injection of 123I-IBF (167 MBq). Additional SPECT scan at three hours (3H-SPECT) and dynamic SPECT scan at most until one hour were performed when possible. No severe side effects due to 123I-IBF injection were observed. The sensitivity, specificity and accuracy for discriminating PS from PD using the striatal specific binding count-to-frontal cortex count ratio (St/Fc-1) in 3H-SPECT were 72.7%, 81.0% and 78.1% in 64 clinically definite cases (i.e., typical cases), respectively. The putamen-to-caudate ratios were significantly lower in striatonigral degeneration compared with those in PD. The contralateral-to-ipsilateral ratios against the symptomatic side of tremor and/or rigidity in the patients with PD (Hoehn & Yahr I) were significantly higher than the left-to-right ratios in the normal controls. St/Fc-1 in 3H-SPECT was significantly lower in the patients showing a poor response to levodopa than in those showing a good response. The dopamine D2 receptor binding potential (k3/k4), obtained by dynamic SPECT based on compartment model analysis, correlated well with the striatal specific binding count-to-occipital cortex count ratio. These results suggest that 123I-IBF is a promising agent for differential diagnosis and pathophysiological evaluation of PD and PS.

Adult↗
PubMed1998

Genetic basis of human complement C8 alpha-gamma deficiency.

Deficiency of the alpha-gamma subunit of the eighth component of complement (C8alpha-gammaD) is frequently associated with recurrent neisserial infections, especially meningitis caused by Neisseria meningitidis. We here report the molecular basis of C8alpha-gammaD in two unrelated Japanese subjects. Screening all 11 exons of the C8alpha gene and all 7 exons of the C8gamma gene and their boundaries by exon-specific PCR/single-strand conformation polymorphism demonstrated aberrant single-stranded DNA fragments in exon 2 of C8alpha gene in case 1 and in exons 2 and 9 of C8alpha gene in case 2. Nucleotide sequencing of the amplified DNA fragments in case 1 revealed a homozygous single-point mutation at the second exon-intron boundary, inactivating the universally conserved 5' splice site consensus sequence of the second intron (IVS2+1G-->T). Case 2 was a compound heterozygote for the splice junction mutation, IVS2+1G-->T, and a nonsense mutation at Arg394 (R394X). R394X was caused by a C to T transition at nucleotide 1407, the first nucleotide of the codon CGA for Arg394, leading to a stop codon TGA. No mutations were detected in the C8gamma gene by our method. Our results indicate that the pathogenesis of C8alpha-gammaD might be caused by heterogeneous molecular defects in the C8alpha gene.

Adult↗
PubMed1998

An ion channel of the degenerin/epithelial sodium channel superfamily controls the defecation rhythm in Caenorhabditis elegans.

Ultradian rhythms are widespread phenomena found in various biological organisms. A typical example is the defecation behavior of the nematode Caenorhabditis elegans, which repeats at about 45-sec intervals. To elucidate the mechanism, we studied flr-1 mutants, which show very short defecation cycle periods. The mutations also affect some food-related functions, including growth rate, the expulsion step of defecation behavior, and the regulation of the dauer larva (a nonfeeding, special third-stage larva) formation in the unc-3 (Olf-1/EBF homolog) background. The flr-1 gene encodes a novel ion channel belonging to the DEG/ENaC (C. elegans degenerin and mammalian epithelial sodium channel) superfamily. A flr-1::GFP (green fluorescent protein) fusion gene that can rescue the flr-1 mutant phenotypes is expressed only in the intestine from embryos to adults. These results suggest that FLR-1 may be a component of an intestinal regulatory system that controls the defecation rhythm as well as other functions.

Activity Cycles↗
PubMed1998

V-ATPase of Thermus thermophilus is inactivated during ATP hydrolysis but can synthesize ATP.

The ATP hydrolysis of the V1-ATPase of Thermus thermophilus have been investigated with an ATP-regenerating system at 25 degreesC. The ratio of ATPase activity to ATP concentration ranged from 40 to 4000 microM; from this, an apparent Km of 240 +/- 24 microM and a Vmax of 5.2 +/- 0.5 units/mg were deduced. An apparent negative cooperativity, which is frequently observed in case of F1-ATPases, was not observed for the V1-ATPase. Interestingly, the rate of hydrolysis decayed rapidly during ATP hydrolysis, and the ATP hydrolysis finally stopped. Furthermore, the inactivation of the V1-ATPase was attained by a prior incubation with ADP-Mg. The inactivated V1-ATPase contained 1.5 mol of ADP/mol of enzyme. Difference absorption spectra generated from addition of ATP-Mg to the isolated subunits revealed that the A subunit can bind ATP-Mg, whereas the B subunit cannot. The inability to bind ATP-Mg is consistent with the absence of Walker motifs in the B subunit. These results indicate that the inactivation of the V1-ATPase during ATP hydrolysis is caused by entrapping inhibitory ADP-Mg in a catalytic site. Light-driven ATP synthesis by bacteriorhodopsin-VoV1-ATPase proteoliposomes was observed, and the rate of ATP synthesis was approximately constant. ATP synthesis occurred in the presence of an ADP-Mg of which concentration was high enough to induce complete inactivation of ATP hydrolysis of VoV1-ATPase. This result indicates that the ADP-Mg-inhibited form is not produced in ATP synthesis reaction.

Adenosine Diphosphate↗
PubMed1998

The formation or the reduction of a disulfide bridge on the gamma subunit of chloroplast ATP synthase affects the inhibitory effect of the epsilon subunit.

We have studied the change of the catalytic activity of chimeric complexes that were formed by chloroplast coupling factor 1 (CF1) -gamma, alpha and beta subunits of thermophilic bacterial F1 after formation or reduction of the disulfide bridge of different gamma subunits modified by oligonucleotide-directed mutagenesis techniques. For this purpose, three mutant gamma subunits were produced: gamma Delta194-230, here 37 amino acids from Pro-194 to Ile-230 are deleted, gammaC199A, Cys-199 is changed to Ala, and gamma Delta200-204, amino acids from Asp-200 to Lys-204 are deleted. All of the chimeric subunit complexes produced from each of these mutant CF1-gamma subunits and alpha and beta subunits from thermophilic bacterial F1 lost the sensitivity against thiol reagents when compared with the complex containing wild-type CF1-gamma. The pH optimum (pH 8.5-9.0) and the concentration of methanol to stimulate ATPase activities were not affected by these mutations. These indicate that the introduction of the mutations did not change the main features of ATPase activity of the chimeric complex. However, the interaction between gamma subunit and epsilon subunit was strongly influenced by the type of gamma subunit itself. Although the ATPase activity of the chimeric complex that contained gamma Delta200-204 or gammaC199A was inhibited by the addition of recombinant epsilon subunit from CF1 similarly to complexes containing the reduced wild-type gamma subunit, the recombinant epsilon subunit did not inhibit the ATPase of the complex, which contained the oxidized form of gamma subunit. Therefore the affinity of the epsilon subunit to the gamma subunit may be dependent on the state of the gamma subunit or the epsilon subunit may bind to the oxidized form of gamma subunit in a mode that does not inhibit the activity. The ATPase activity of the complex that contains gamma Delta194-230 was not efficiently inhibited by epsilon subunit. These results show that the formation or reduction of the disulfide bond on the gamma subunit may induce a conformational change in the region that directly affects the interaction of this subunit with the adjacent epsilon subunit.

Amino Acid Sequence↗
PubMed1998

ATP synthesis by F0F1-ATP synthase independent of noncatalytic nucleotide binding sites and insensitive to azide inhibition.

ATP hydrolyzing activity of a mutant alpha3beta3gamma subcomplex of F0F1-ATP synthase (DeltaNC) from the thermophilic Bacillus PS3, which lacked noncatalytic nucleotide binding sites, was inactivated completely soon after starting the reaction (Matsui, T., Muneyuki, E. , Honda, M., Allison, W. S., Dou, C., and Yoshida, M. (1997) J. Biol. Chem. 272, 8215-8221). This inactivation is caused by rapid accumulation of the "MgADP inhibited form" which, in the case of wild-type enzyme, would be relieved by ATP binding to noncatalytic sites. We reconstituted F0F1-ATP synthase into liposomes together with bacteriorhodopsin and measured illumination-driven ATP synthesis. Remarkably, DeltaNC F0F1-ATP synthase catalyzed continuous turnover of ATP synthesis while it could not promote ATP-driven proton translocation. ATP synthesis by DeltaNC F0F1-ATP synthase, as well as wild-type enzyme, proceeded even in the presence of azide, an inhibitor of ATP hydrolysis that stabilizes the MgADP inhibited form. The time course of ATP synthesis by DeltaNC F0F1-ATP synthase was linear, and gradual acceleration to the maximal rate, which was observed for the wild-type enzyme, was not seen. Thus, ATP synthesis can proceed without nucleotide binding to noncatalytic sites even though the rate is sub-maximal. These results indicate that the MgADP inhibited form is not produced in ATP synthesis reaction, and in this regard, ATP synthesis may not be a simple reversal of ATP hydrolysis.

Adenosine Triphosphate↗
PubMed1998

Transition Dipole Moments for the Vibrational Fundamentals of HNC Determined from the Herman-Wallis Effect.

The nu1 and nu3 fundamental bands of HNC are recorded with a Fourier transform infrared spectrometer with a resolution of 0.008 cm-1. Hydrogen isocyanide is generated in situ by dc discharge in a mixture of CH3CN ( approximately 40 mTorr), H2 ( approximately 160 mTorr), and Ar ( approximately 160 mTorr). The transition dipole moments for these fundamental bands are determined from the analysis of the Herman-Wallis effect, and they are compared with ab initio calculated values. It is found that the ab initio values for the nu1 and nu3 bands are about 50 and 30% larger, respectively. The transition dipole moments determined are to be of use for determination of the abundance of HNC in reaction systems such as the dissociative recombination reaction of HCNH+ with electrons. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Endobronchial hamartoma treated by an Nd-YAG laser: report of a case.

Endobronchial hamartomas are only rarely encountered. They cause irreversible lung damage due to bronchial obstruction if not diagnosed early and treated properly. Among the various treatments for this rare disease, a surgical resection remains the most popular. We herein report a case of a 53-year-old man presenting with an endobronchial hamartoma which was successfully excised by laser irradiation via a rigid bronchoscope, along with a review of 113 patients with this disease reported in the literature.

Bronchial Diseases↗
PubMed1998

Cytochemical and patch-clamp studies of calcium influx through voltage-dependent Ca2+ channels in vestibular supporting cells of guinea pigs.

To clarify whether or not vestibular supporting cells have voltage-dependent Ca2+ channels, cytochemical and patch-clamp studies were performed using cells isolated from the ampullae of the semicircular canal of the guinea pig. Image analysis used fura-2 as a Ca(2+)-sensitive fluorescence dye and showed that the intracellular Ca2+ concentration ([Ca2+]i) increased with bath application of high (150 mM)K+, but was unaffected by 80 mM K+. The increase in [Ca2+]i induced by high K+ was completely blocked by 1 microM nifedipine as an L-type Ca2+ channel antagonist. In the patch-clamp whole-cell recording of the isolated supporting cells, the voltage-dependent inward current was induced by a depolarizing pulse lasting 2 s in a high (50 mM) Ca2+ and tetraethylammonium-containing external solution replaced by choline chloride and a Cs(+)-containing internal solution. The inward current was obtained when the membrane was depolarized to -50 mV and maximum current was observed at -10 to +10 mV. This inward current was completely blocked by 1 microM nifedipine. These findings strongly suggest that voltage-dependent Ca2+ channels exist in the vestibular supporting cells and regulate Ca2+ concentration in the vestibular endolymph.

Animals↗
PubMed1998

Novel mutations of the peripheral myelin protein 22 gene in two pedigrees with Dejerine-Sottas disease.

Peripheral myelin protein 22 (PMP22), a membrane glycoprotein, plays a significant role in the formation and/or maintenance of compact myelin in the peripheral nervous system. We studied two pedigrees with Dejerine-Sottas disease and identified two novel mutations in the PMP22 gene: one a 2-bp deletional mutation at nucleotide positions 426 and 427 of exon 4 (this is predicted to alter the reading frame at leucine 80 and thus to lead to frame-shifted translation), and the other a guanine to thymine substitution at nucleotide position 636 leading to a cysteine substitution for glycine 150. Both mutations were located in the putative transmembrane domains reported in many cases of Charcot-Marie-Tooth neuropathy, Dejerine-Sottas disease, and hereditary neuropathy with liability to pressure palsies. The results suggest an important role for the putative transmembrane domains of PMP22 in its function.

Adult↗
PubMed1998

Gastric emptying after pylorus-preserving gastrectomy in comparison with conventional subtotal gastrectomy for early gastric carcinoma.

It is well known that surgical intervention on the stomach will greatly alter gastric function and gastric emptying. In this study, we evaluated the difference in postoperative gastric remnant emptying following pylorus-preserving gastrectomy (PPG) and conventional subtotal gastrectomy (CDG) using sulfamethizole capsule food. The subjects comprised 18 patients who underwent PPG and 23 who underwent CDG for early gastric carcinoma. While delayed gastric emptying was observed early after PPG, 1 year after PPG it was markedly accelerated compared with that measured in the early postoperative period. However, it was slower than that in the CDG patients. On the other hand, rapid gastric emptying was observed early after CDG and did not change with time. These findings stress that although PPG results in stasis in the early postoperative period, it seems to prevent unduly rapid emptying.

Anti-Infective Agents↗
PubMed1998

Metamorphosis-associated and region-specific expression of calbindin gene in the posterior intestinal epithelium of Xenopus laevis larva.

The present study used a molecular approach toward understanding the mechanism of hormone- and region-dependent remodeling of the small intestine during metamorphosis of Xenopus laevis. A protein spot was noticed on a two-dimensional polyacrylamide gel as a protein whose expression was metamorphic stage- and region-dependent. The protein was identified as the Xenopus homolog (Xcalbindin) of chick calbindin D28k. Xcalbindin expression in the intestine was restricted to absorptive cells in the posterior part, being detectable at stages 49-61, not detectable at stages 62-63, detectable again at stages 64-66, and finally becoming undetectable in the adult. During spontaneous metamorphosis, the level of Xcalbindin mRNA was significantly increased between stages 57 and 58, dramatically reduced at stage 59, and the mRNA was undetectable from stages 60-63, after which it was weakly re-expressed until the end of metamorphosis. Such up- and down-regulation of Xcalbindin mRNA was induced precociously by exogenous thyroid hormone. These results indicated that Xcalbindin is a specific marker of the differentiated absorptive cells of the intestine. Immunohistochemistry with specific antibodies against Xcalbindin demonstrated that precursor cells of adult intestinal epithelial cells expressed Xcalbindin. Considering these results, the origin of adult intestinal epithelial cells was discussed.

Amino Acid Sequence↗